With new advances in telescopes, researchers learn about past, future

Dec. 2, 2013

The farthest and one of the very earliest galaxies ever seen in the universe appears as a faint red blob (squared in upper right image) in this ultra-deep–field exposure taken with NASA's Hubble Space Telescope. This is the deepest infrared image taken of the universe. / Courtesy of NASA, ESA, G. Illingworth, R. Bouwens

Written by

Amanda Oglesby and Hart Sastrowardoyo

and Traci Watson

The newly discovered galaxy, named MACS0647-JD, is very young and only a tiny fraction of the size of our Milky Way. The object is observed 420 million years after the big bang. The inset at left shows a close-up of the young dwarf galaxy. This image is a composite taken with Hubble's WFC 3 and ACS on Oct. 5 and Nov. 29, 2011. / NASA, ESA, and M. Postman and D. Coe (STScI) and C

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Peer up into the night sky this time of year and some of the twinkling star light that hits your eyes may be thousands, maybe even millions, of years old.

The sky essentially is tons of ancient snapshots, images of objects in space as they once existed in the past. Starlight travels across the vastness of the cosmos, showing humans not what exists now, but what once was.

“When you’re looking up at the night sky, you’re looking back at different stages of history and seeing the light as it was when it left there some millions, or hundreds, or dozens of years ago,” said Kevin Gallagher, president of S.T.A.R. (the Society of Telescopy, Astronomy and Radio) based in Lincroft. “Something could have happened (to those stars), and it will be a long time before we find out.”

For the past few years, scientists have been engaged in a fierce competition to find the most distant galaxies in the cosmos, galaxies that existed less than a billion years after the Big Bang, the colossal explosion that founded the universe. The quest has shed light on the evolution of the young universe, but now researchers hope to pinpoint the onset of “cosmic dawn,” when starlight from newborn galaxies first bathed the universe.

Snaring a distant galaxy is challenging. The farthest galaxies are, to human eyes, “literally invisible,” said the University of Texas-Austin astrophysicist Steven Finkelstein. He explained that when light from far-off galaxies travels to telescopes in our neck of the cosmic woods, any visible light is transformed along the way into a light “redder than our eyes can see,” though it’s visible to the right kind of cameras and telescopes.

The information encoded in the “redshifted” light gives scientists a picture of galaxies as they were billions of years ago — essentially the baby pictures of the universe. The farther away the galaxy, the further back in time we see.

“Telescopes are time machines (that) let us peer back into the past,” said astrophysicist Garth Illingworth of the University of California-Santa Cruz, via email. “The light from distant objects takes so long to reach us that we see them when they were much younger.”

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Gallagher, of S.T.A.R., said his six-foot high, backyard telescope — though impressive as far as amateur stargazing goes — cannot detect these so distant galaxies.

“A lot of it depends on what your sky conditions are,” he said. “The challenging thing about being an observing amateur astronomer in New Jersey is you’ve got a lot of light pollution to deal with.”

His own telescope can see stars being born in the Orion nebula, a gas and dust-filled cosmic nursery. It detects globular star clusters as old as our own Milky Way galaxy, that are tens of thousands of light years from Earth. He can even see one of the Milky Way’s closest cosmic neighbors, the Andromeda galaxy, which lies about 2.5 million light years away.

For years, scientists with the best telescopes could peer back no further than roughly 12 billion years ago, when the universe was about 780 million years old. Finally, in 2009, astronauts fitted the Hubble Space Telescope with a new camera, called Wide Field Camera 3, that revolutionized the galaxy-hunting business. Wide Field 3 is far more efficient than its predecessor on the Hubble, and it can see very red light, just the right color for detecting the most distant galaxies.

“What we saw (through Hubble) is that in fact there are no blank portions of the sky,” Gallagher said. “It’s just an enormous assortment of galaxies that go back to near the dawn of the universe.”

When Wide Field 3 produced its first batch of data in 2009, competing groups of scientists quickly found dozens of galaxies much deeper in time than seen before.

Hubble “is the single greatest scientific instrument ever created,” Gallagher said. “That’s pretty exciting stuff — getting closer to understanding the questions surrounding the creation of the universe. It’s about as exciting as you can get.”

Scientists now have a much deeper understanding of the universe, not only of its beginnings, but of its future.

“The further out in distance — you’re looking further back in time — the galaxies are different. They’re smaller,” said Richard Brady, an adjunct professor of astronomy at Ocean County College and president of the Astronomical Society of the Toms River Area, a stargazing group. “The initial ones were smaller, they were closer together, and over time they would collide and form larger galaxies.”

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Our own Milky Way is on such a collision course, he said. It will merge with the Andromeda galaxy in more than 3 billion years. Until then, Andromeda will appear to grow in the sky as it moves closer, he said.

At the same time, other galaxies are racing away from us as the universe expands, Brady said. Eventually, other galaxies will be so far away, that we may no longer be able to detect them, he said.

“Eventually we’ll just be able to see our galaxy, and a few surrounding galaxies and nothing beyond that,” Brady said.

Though there’s still much to learn, Hubble can’t help much more. The telescope has looked about as far back as it can possibly see, and now researchers are waiting eagerly for the opening of an array of new ground-based telescopes and for the 2018 launch of NASA’s James Webb Space Telescope, which should allow researchers to detect galaxies not long after the Big Bang.

The telescope is expected to collect the infrared light of galaxies invisible to Hubble, Brady said. Even with the Webb telescope, the ever expanding universe may withhold some of its secrets.

“There may be parts of the universe we can’t see,” Brady said. “We’re not sure exactly what’s beyond that horizon.”